Death Bringer

I
t is said that the now dead god Bhaal foresaw his
death during the Time of Troubles and came to
material plain before the climactic event. He mated
with females of almost any species, not all of them
humaniod. Bhaalspaen is the name given to the
mortal offspring, for they hield some of his divine
spark. He would attempt to use these offspring to
bring himself back to life. Alaundo the Seer made a prophecy
about the Bhaalspawn that foretold the great destruction they
would bring, but even he couldn't see that this divine trait
would reapper for years to come.
The Creation of the Bhaalspawn
The Lord of Murder shall perish
But in his doom he shall spawn a score of
morttal progeny
Chaos will be sown from their passing
So sayeth the wise Alaundo

Nature
Bhaalspawn mostly seemed like normal members of their
race at first, so long as the race was humanoid. As they grew
older, the divine part of there soul would eventualy awaken
often granting supernatural, but usually also tempting them
to evil and murder.
Individual reactions were very different, however. The
personalities of individual Bhaalspawn were just as varied as
those of other people, but they all had to deal with similar
issues when their other side manifested itself. Many fell to
the temptation of power and embraced their dark sides.
Others, weak-willed rather than power-hungry, had no such
ambitious goals and may have even tried to do what was
right, but reveled in bloodshed nevertheless.

Bloodlust

At 3rd level, the bhaalspawn essence inside of you has started
showing, giving you an edge when you fight.
Once an enemy has dropped bellow half health, you have
advantage on all melee attack roles against them.

Blood Drain

At 7th level, the bhaalspawn essence inside of you starts
healing you in battle.
When you melee attack a creature as an action, you can
spend bonus action to absorb half the amount of hitpoints
you dealt as an action.

Unholy Might

At 10th level, the bhaalspawn essence inside you has started to
refine and purify itself. Allowing you to draw upon Bhaals might.
When you deal damage with a melee weapon, you
add your bhaalspawn level to the amount of damage that
attack dealt.

Limited Skill Improvement

At 13th level, Bhaals essence gives you permanent +1 to
Constitution and Strength. This bonus cannot make a stat go
over 20.

Pocket Plane

At 15th level, the power of Bhaal allows you and your party to
go to a pocket plane inside of the realm of murder.
This acts similarly to the spell Mordenkainen’s Magnificent
Mansion, with the following exceptions.
The place is an 80 ft radius sphere that completely black
floor and ceiling with a single burning fire in the center.
The walls are smeared with a dark red material
There is a 10 x 10 x 10 ft square of water that magically
refills.
There was an imp, Cespenar, that acts as a butler for the
area. He also is known to create magical items for a price.

Slayer Form

At 18th level, the essence of Bhaal mixed with your own
allowing you to become his divine avatar for a time.
Once per week, as an action you can turn into the Slayer
From for ten minutes. When you transform into the Slayer, all
your clothes and gear get absorbed into your skin that
becomes bright blood red. You gain the following attributes:
You gain 100 temporary hit points
You become resistance to non-magical bludgeoning,
piercing and slashing damage.
Your Strength, Dexterity, and Constitution becomes 25
Your size becomes large
Your AC becomes 18
You gain Magic Resistance
Your melee attack becomes 1d6 + Strength Mod
You gain four attacks per round
You can't cast spells
You become immune to being stun, charmed, restrained,
blinded, deafened, frightened, prone, and paralyzed.
After being in this form ends you take a point of
exhaustion.